Any good DIY amps for low impedence/high sensitivity headphones? - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st June 2012, 11:49 AM   #11
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by ethanolson View Post
I'm with @jcx on this one. I recommend you go after a CMOY with unity gain (i.e. a buffer), but configured with <1Z to get all the benefit possible from your 'phones.
I really DONT think jcx was thinking to the cmoy, nor any other IC-based output stage cause they dont have the required current to drive low Z 'phones.
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 21st June 2012, 01:54 PM   #12
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
some single op amps have plenty of current, but may not like the load Z

adding series R is OK for flat impedance curve headphones, can make a R divider "L-pad" but then need excess current capacity to "waste" in order to get lower drive Z to the headphone (== deliberate Z mismatching)


at the extreme it depends on what you consider low z, high sensitivity

JH Audio JH16 IEM:
118dB @ 1mW
Impedance: 18 Ohms

~200 mV, 10 mA peak to get to ~120 dB SPL

clearly the only rational way to drive these from 1-2 Vrms standard audio sources involves a step down transformer

Last edited by jcx; 21st June 2012 at 01:58 PM.
  Reply With Quote
Old 21st June 2012, 02:54 PM   #13
haejuk is offline haejuk  United States
diyAudio Member
 
Join Date: Apr 2012
Location: Northern VA
I have pretty much decided to build a 2 channel Beta22 with low gain. I may get other headphones in the future and have to change the gain settings, but a Beta22 should drive anything I throw at it admirably.

I had looked into making something that is just a current source + attenuator, but there don't seem to be any viable (well documented) designs.

In fact, I think it was a post on another forum by jcx that convinced me to go 2 channel on my Beta22 build instead of 3 channel.

Last edited by haejuk; 21st June 2012 at 02:59 PM.
  Reply With Quote
Old 21st June 2012, 03:12 PM   #14
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
TPA6120 is designed for 25 Ohm load, good audio specs by itself - some headphone project amps use it

some may not know but CFA op amps can be used "unity gain" - you still need a feedback R between the output and -in
its value provides frequency response compensation, increasing it provides "overcompensation" - less peaking, better immunity to destabilizing C load

better (but probably inaudible) performance can be had by wrapping a "good", "audio" input op amp feedback loop around a CFA buffer op amp in a multiloop composite amplifier
  Reply With Quote
Old 21st June 2012, 04:28 PM   #15
diyAudio Member
 
Join Date: Nov 2011
Location: http://binged.it/ukmr5Y
I've been liking the use of the NJM4556D that the Objective2 employs. That thing can handle 1 Ohm to 600 Ohm and puts out about 70mA... enough for every headphone out there (other than the K1000) to get over 105dB.

Anyway, I was thinking you would've liked to build something like this: http://nwavguy.blogspot.com/2011/05/...phone-amp.html

I hope the Beta22 turns out nicely.

Last edited by ethanolson; 21st June 2012 at 04:34 PM. Reason: I'm smarter now than I was before.
  Reply With Quote
Old 21st June 2012, 06:17 PM   #16
haejuk is offline haejuk  United States
diyAudio Member
 
Join Date: Apr 2012
Location: Northern VA
I did actually build an Objective2, and I think that it simply can't be beat for the price of parts, or its retail price for that matter. I had considered building another one and putting it in a larger enclosure for desktop use, but decided to try a Beta22. I might take a crack at some of the other amps mentioned in this thread as well, since I find building these things just as much fun as listening to them.
  Reply With Quote
Old 22nd June 2012, 02:38 PM   #17
diyAudio Member
 
Join Date: Mar 2012
Other than the B22, AMB has a few other offerings such as the CKKIII, M3, or even the A20 that can be configured as unity gain buffer. Or you can make a simple tube voltage gain stage to drive the A20 buffer if you fancy a hybrid.

I have only build the B22 but all of them are supposed to be good. Glass jar audio offer kits for some of these and all you have to do is put them together.

They also have other kits such as the SOHA II, EHHA and the Bijou from Cavalli audio. FWIW I prefer the SOHA II over the B22.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
What is better: low or high sensitivity microphones ? Web Wolf Multi-Way 4 7th May 2006 10:35 PM
High Sensitivity, low cost bookshelf speakers? jonnythan Multi-Way 7 1st March 2006 12:50 AM
New to DIY... Looking for something w/ high sensitivity. DonoMan Multi-Way 25 10th February 2005 02:58 AM
High impedance out amps VS as low as possible. Brian Guralnick Solid State 57 31st October 2002 07:47 PM


New To Site? Need Help?

All times are GMT. The time now is 06:46 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2